Our hunger for a weight-loss miracle

Dieting is our national repast-time

This product image provided by Vivus Pharmaceuticals Inc. shows bottles of Qsymia, the company's anti-obesity drug. The pill was approved Tuesday, July 17, 2012 by the Food and Drug Administration for patients who are overweight or obese and also have at least one weight-related condition such as high blood pressure, diabetes or high cholesterol. (AP Photo/Vivus Pharmaceuticals Inc.)
— AP

This product image provided by Vivus Pharmaceuticals Inc. shows bottles of Qsymia, the company's anti-obesity drug. The pill was approved Tuesday, July 17, 2012 by the Food and Drug Administration for patients who are overweight or obese and also have at least one weight-related condition such as high blood pressure, diabetes or high cholesterol. (AP Photo/Vivus Pharmaceuticals Inc.)
/ AP

Document

Document

With about two-thirds of American adults overweight or obese, it’s no surprise that dieting is our national repast-time.

At any given moment, up to half of all American women (and 25 percent of men) say they are actively attempting to lose weight by changing what and how much they eat.

“The majority of the nation is perpetually dieting, feeling guilty, eating alone, while driving in their cars, etc.,” said Andrea Garber, an associate professor of pediatrics and chief nutritionist for UC San Francisco’s adolescent eating disorders program and its child obesity clinic. “(Food writer) Michael Pollan calls it ‘our national eating disorder.’ ”

The typical attempt at dieting begins informally and unsupervised: We vow to eat less, to eat better, to cut down on things like sweets and soda. When that doesn’t work, we turn to commercial remedies, of which there are many, from Weight Watchers, Atkins and The Zone to South Beach, Dukan and the so-called Paleolithic Diet.

All of these diet regimes operate on the same basic premise: Reduce caloric intake. But simply telling consumers to consume less doesn’t sell many books, videos, meal plans, devices and smartphone apps, so commercial diets tend to key upon reducing a particular source of calories — low-fat or low-carbohydrate, say — or how those calories are used by the body.

The Paleo diet, for example, urges practitioners to eat like hominids, though it is quite unlikely that ancestral hunter-gatherers would recognize most modern fare.

Some diets emphasize basic biological aspects or variations in people, such as how food may affect gene activity (nutrigenomics) or differences in individual basal metabolic rates (the amount of energy expended at rest) or blood types.

The science supporting many of these diets is confounding and contradictory. Often, it’s dubious. Sometimes, it doesn’t exist. Moreover, said Dr. Will Yancy, a professor of medicine and weight-loss researcher at Duke University, no diet works for everyone, every time.

“It is not clear if one single approach is better than the others,” said Yancy, “but some approaches may be better for some individuals.”

Yet all commercial diets promise success, despite abundant evidence to suggest most inevitably fall short. They prove unsustainable, for example, or the weight loss is transient. The frequently cited rate of diet failure is 95 percent, though some critics claim it’s really higher.

Nature can take some of the blame. While it’s relatively easy to lose initial pounds, our bodies eventually push back, adjusting metabolic and cellular activities to resist further weight loss. It’s a survival mechanism involving a phenomenon called homeostasis intended to preserve a biological status quo.

Unfortunately for dieters, the more they weigh, the longer they remain at that weight, the higher their homeostatic point can become and the more difficult it becomes to reset it to an earlier, lower weight.